Activity Concentrations Of Radionuclides Research Articles

Field-based soil-plant uptake measurements of natural radionuclides for key vegetables and ghaf leaves in Abu Dhabi

With the thriving fossil fuel and nuclear based industries in the nation, radioecology has become necessary for the radiation safety and emergency-preparedness for the United Arab Emirates (UAE). Environmental radiation transport modelling in the UAE and the Arabian Peninsula are severely limited, as we discuss in this paper, due to lack of experiments specific to arid desert climates. To fill the missing gaps in the baseline arid region radioecological database, especially for the soil-plant uptake studies, rigorous field works have been conducted for the first time on the soil and plant in the farms and open fields of the UAE. We present Abu Dhabi based measurements of activity concentrations of radionuclides of natural origins, in soils, key vegetables (cucumber, tomato, and bell pepper), and leaves of ghaf - a prominent native tree. The empirical data are utilized to get the first published estimates of UAE-specific plant-soil concentration ratios (CR), measuring root uptake of radionuclides in nonleafy vegetables and native trees. Such systematic studies are very rare for arid sandy soils. For the 27 samples analyzed, the activity concentrations' (unit Bq kg−1) ranges are: 169–1746 for 40K, 12–19.5 for 226Ra, and 2.7–23.1 for 228Ra. Likewise, wide variability is seen in the averages of concentration ratios also, ranging in 1.05–4.94 for 40K, 0.14–1.82 for 226Ra, and 0.53–2.78 for 228Ra. A net bioaccumulation (concentration ratio >1) of some of these natural radionuclides is found in many samples, but no significant doses or hazard indices are found due to these three radionuclides in the UAE's soils and vegetations. The paper discusses the careful work through tens of field sampling exercises, well controlled sample processing, high resolution gamma spectrometry, and treatment of data from gamma counting rates to accumulated dose rate estimations.

Evaluation of Radioactivity and Radiological Parameters in Soil Samples in Isparta, Türkiye

In the city centre of Isparta, located in the southwestern part of Türkiye, indoor radon concentrations and gamma dose rate levels were observed above the world and country averages. For this reason, the determination of the natural radioactivity levels in soil samples of Isparta province is of great interest. In the present study, the activity concentrations of radionuclides (namely 226Ra,232Th, 40K and 137Cs) were investigated in the soil samples collected from 72 different points including the city centre and 12 towns of Isparta by using a gamma spectrometer with a high-purity germanium (HPGe) detector. The activity concentrations of 226Ra,232Th, 40K and 137Cs radionuclides in the samples were found in the range of 4.08±0.39 - 69.84±1.43 Bqkg-1, 2.63±0.28 - 65.66±1.41 Bqkg-1, 44.48±3.17 - 452.38±9.65 Bqkg-1 and 0.28±0.18 - 19.10±0.61 Bqkg-1 respectively. The averages of all the measurements were determined as 15.69±0.72 Bqkg-1 for 226Ra, 15.40±0.78 Bqkg-1 for 232Th, 210.60±6.22 Bqkg-1 for 40K and 3.44±0.31 Bqkg-1 for 137Cs. Although these values were below the country and world averages, it was revealed that the 226Ra and 232Th activity concentrations in the city centre exceeded the national and world averages. In addition, radiological risk maps of the analysed radionuclides were produced for the first time, covering all towns within the Isparta province. To evaluate the radiological hazards resulting from natural radionuclides, external hazard index (Hex), absorbed dose rate (D), annual effective dose equivalent (AEDE), male and female lifetime cancer risk (LCR) values were also calculated. The outcomes of this study revealed that all the radiological parameter averages for Isparta were lower than the world and country averages but the calculation results for the city centre displayed the opposite of this situation except for the external hazard index.

Evaluation of radioactivity concentration in farm fresh milk and concomitant dose to consumer

In this study, activity concentrations of natural radionuclides in 28 raw milk samples collected from different dairy farms in Dhaka city of Bangladesh were measured using a high-purity germanium (HPGe) detector for the first time. The activity concentration of 226Ra, 232Th, and 40K in the investigated fresh milk samples ranged from BDL (Below detection level) to 26 ± 1.6 Bq/kg, BDL to 11.7 ± 3.3 Bq/kg and 101 ± 17 to 384 ± 32 Bq/kg, respectively. No artificial radionuclides were found in the investigated samples. Present results show inline within the range of available data in the literature. Annual committed effective doses were estimated following the consumption characteristics of raw milk by city population, values are found within the limiting range recommended by international organizations due to consumption of foodstuffs. Additionally, real-time gamma-ray dose rate in the farms/sampling locations was found in the range of 0.12 ± 0.01–0.20 ± 0.01 μSv/h by using a digital gamma survey meter (Gamma Scout) and the calculated maximum annual effective dose due to outdoor absorbed dose was found to be 0.25 mSv/y, which shows lower than the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended limit of 2.4 mSv/y. This study indicates that the concentration of radionuclides in the farm fresh milk of Dhaka city does not pose any unwanted risk to public health, and it is safe to consume by both children and adults with the current intake level.

Study on the behavior of radionuclides in geologic samples from fault zone, Gabal Um Hamd, southwestern Sinai, Egypt

The present study concerned with the activity concentrations of natural radionuclides (238U, 234U, 230Th, 226Ra, 232Th, 40K and, 235U) in ten sedimentary rock samples collected from fault zone, Gabal Um Hamd, southwestern Sinai, Egypt. These samples were investigated to study their behavior during a part of geologic time. The activity concentrations were measured using γ-ray spectrometry (HPGe detector). The investigated samples were analyzed for major oxides using the XRF technique. The results demonstrated high average activity concentrations of 238U, 234U, 230Th, 226Ra, 232Th, 40K and, 235U than the worldwide average values as reported by UNSCEAR 2008. Theil diagram showed that there are accumulation and leaching of uranium in some samples in the two sides of the fault zone. It is noticed that the ages of uranium depositions for the samples collected from the downthrown of the fault zone vary from 121.5 to 440.1 ky, while for the sample collected from the upthrown of the fault is 210.9 ky. The 230Th/232Th activity ratios range between 4.55 and 91.04 for downthrown samples and between 4.75 and 6.05 for upthrown samples which are smaller than 20 except for two samples, indicating a contamination of the samples by detrital 230Th. After subtraction of the detrital 230Th, the corrected ages for downthrown samples vary from 119.1 to 231.7 ky while for upthrown samples vary from 164.4 to 390 ky.

Radiological Assessment and Potential Health Risks of Tailings from Komu, Southwestern Nigeria

There are reports that radionuclides found in mining tailings pose significant challenges to the natural environment and cause health risks to humans. The study investigated the levels of activity concentrations of 226Ra, 232Th and 40K radionuclides, as well as radiological hazard indices in tailings sourced from Komu, a community emblematic of mining activities in the Southwest of Nigeria. Thirty (30) tailing samples were collected and analysed by a High-purity Germanium (HpGe) detector. The results revealed high activity concentrations of these radionuclides exceeding global averages and indicating potential health risks. The activity concentration of 226Ra ranged between 312.07 and 851.14 Bq/kg, with an average of 652.86 Bq/kg. Similarly, the activity concentration of 232Th ranged between 33.31 and 160.10 Bq/kg, with an average of 116.26 Bq/kg. In addition, the activity concentration of 40K ranged between 96.11 and 1184.65 Bq/kg, with an average of 717.53 Bq/kg. The radiological hazard indices considered in this study exceeded the internationally accepted safety limit for building construction materials. These findings indicate heightened exposure risks, emphasizing the need for regulatory measures to mitigate hazards associated with tailings sourced from Komu, particularly for building construction purposes.

Radiological hazards assessment of building materials used in Swakopmund, Namibia

A Canberra coaxial High Purity Germanium (HPGe) gamma-ray spectrometry detector was used to measure activity concentrations of radionuclides in commonly used building materials in Swakopmund, Namibia. The activity concentrations in, Bq.kg−1, for 226Ra, 232Th and 40K in all sample groups of building materials (cement, sand, cement bricks and roof tiles) were found to be in the range of 18.002–499.266, 14.069–132.508 and 162.794–1747.260, respectively. The average activity concentration of 40K was found to be two times higher than the critical level of 500 Bq.kg−1 in sand, cement bricks, clay bricks and roof tiles. The measured activity concentrations were used to estimate average dose rates and radiological hazard parameters. The absorbed dose rate (D) both due to indoor and outdoor exposure was higher than the international acceptable safe limits in all sample groups while the annual effective dose equivalent (AEDE) due to indoor exposure was higher in sand, cement bricks and clay brick samples. AEDE due to outdoor exposure was within acceptable safe limits for all sample groups. Radium equivalent (Raeq), external hazard (Hex) and gamma (Iγ) hazard indices were found to be higher than the acceptable safe limit only in clay bricks samples. The internal hazard (Hin) index was only higher than the acceptable safe limit in cement and clay bricks while the alpha (Iα) index was higher in sand, cement bricks and clay bricks. The Excess Lifetime Cancer Risk (ELCR) exceeded the acceptable safe limits in all sample groups. Our study showed that most of the computed radiological parameters were significantly higher than prescribed safe limits in most of the samples and therefore may pose a health risk to the inhabitants of Swakopmund.

Natural Radioactivity in Raw Building Materials for Underground Parking Lots and Assessment of Radiological Health Risk for the Population.

This article reports the results of an investigation into the activity concentration of natural radionuclides in raw building materials for underground parking lots, together with the assessment of the radiation hazard for the public related to exposure to ionizing radiations. To this purpose, high-purity germanium (HPGe) γ-ray spectrometry was employed in order to quantify the average specific activity of 226Ra, 232Th, and 40K natural radioisotopes. With the aim to assess any possible radiological health risk for the population, the absorbed γ-dose rate (D), the annual effective dose equivalent outdoor (AEDEout) and indoor (AEDEin), the activity concentration index (I), and the alpha index (Iα) were also estimated, resulting in values that were lower than the maximum recommended ones for humans. Finally, the extent of the correlations existing between the observed radioactivity and radiological parameters and of these parameters with the analyzed samples was quantified through statistical analyses, including Pearson's correlation, a principal component analysis (PCA), and a hierarchical cluster analysis (HCA). As a result, three clusters of the investigated samples were recognized based on their chemical composition and mineralogical nature. Noteworthily, this paper covers a certain gap in science since its topic does not appear in literature in this form. Thus, the authors underline the importance of this work to global knowledge in the environmental research and public health fields.

Investigation of radiogeology and environmental geochemistry of quarry ponds in post-tin mining areas of Phuket Island, southern Thailand

Increasing demand for water supply on Phuket Island for both the local consumption and hotel industry has led to overexploitation of ground- and surface water bodies; hence, it is unremittingly important to monitor the local hydrologic regime. Radiogeological and hydrogeochemical environments are investigated by representative water and surface sediment samples collected from the different quarry ponds located in post-tin mining areas on Phuket Island. The study assessed water quality, analyze the relationship between bedrock weathering and water quality, and identify radiogeological factors and natural radon concentrations, with insights into the local geology of the study areas. The representative quarry ponds of Phuket Island consist of a granite quarry pond (PKW1), a Quaternary sediment quarry pond (PKW2), a granitic-metamorphic quarry pond (PKW3), and the perturbation pond (PKW4), with the formation of a variety of geologic features. All collected water samples show total cation concentrations with Ca2+ > Na+ > K+ > Mg2+ and total anion concentrations with HCO3− > Cl− > NO3− > SO42−. However, Gibbs diagrams suggest that rock–water interactions and precipitation are major factors in geochemical processes controlling the water quality. Radon enrichments in the water samples are involved in the local geological structures and hydrogeological environments, as follows: PKW1 > PKW3 > PKW2 > PKW4. No significant correlation between the radon activity concentrations and major/minor ions is shown. Surface sediment samples are reported, and the activity concentrations of radium-228 and thorium-228 (radioactive decay series of thorium-232) are relatively higher than those of radium-226 (radioactive decay series of uranium-238). Therefore, the activity concentrations of natural radionuclides in the surface sediments could be directly influenced by physical weathering, particularly the depositional environments of granitic bedrock around the quarry ponds. Long-term monitoring is necessary to consider the behavior of quarry ponds, which is related to tourism planning and the overall development of Phuket Island.

Radioactivity estimation of baobab (Adonsonia digitata) in katsina metropolis, katsina state Nigeria

Radioactivity estimation of baobab plants was carried out in Katsina metropolis, Katsina State, Nigeria. Samples of soil, roots, and leaves were collected, prepared and analyzed to estimate the activity concentration of the natural radionuclides of U-238, Th-232, and K-40using NaI (TI) gamma ray spectrometry detector. The results obtained showed that the activity concentration ranged from 0.1 Bq/kg to 33.26 Bq/kg, 1.98 Bq/kg to 64.98 Bq/kg and 65.89 Bq/kg to 1009.69 Bq/kg with overall mean values of 11.35, 18.87 and 545.14 in Bq/kg for U-238, Th-232 and K-40 respectively. In order to assess the radiological parameters of the natural radioactivity; the radium equivalent activity (Raeq), an absorbed dose rate and the measured annual effective dose equivalent were calculated and lies in the ranges of 18.83 to 183.22 (Bq/kg), 9.07 to 85.90 nGy/h and 0.011 to 0.105 mSv/y respectively; mean values obtained are 87.20 Bq/kg, 40.55 nGy/h and 0.050 mSv/y respectively. However, the calculated values obtained for all the radiological parameters falls below the world acceptable limits of 370 Bq/kg for Raeq; 89 nGy/h for the absorbed dose rate and 1 mSv/y annual effective dose rate for the general public; for the annual effective dose due to ingestion or inhalation of NORMS in the soil, medicinal plants and food is 0.07 mSv/y and the value is within the acceptable limit of intake; external and internal hazard index were calculated and found to have values of 0.23 Bq/kg for Hex and 0.30 Bq/kg for Hin and are lower than unity set by ICRP. Base on the radiological hazards evaluations, there is no any health risk due to radiation from the natural sources in using the roots and leaves parts of baobab plants for any purposes in the study area. Moreover, the measured soil around the study area was found to be safe and will not pose any radiation exposure to the population. Hence, the research will serve as the baseline for detection of any future released activities of related natural radionuclides especially around the consumable plants. However, effort should be made to ensure that the radiological parameters of the study area are kept as low as reasonably achievable.

Using radial basis artificial neural networks to predict radiation hazard indices in geological materials.

The estimation of exposures to humans from the various sources of radiation is important. Radiation hazard indices are computed using procedures described in the literature for evaluating the combined effects of the activity concentrations of primordial radionuclides, namely, 238U, 232Th, and 40K. The computed indices are then compared to the allowed limits defined by International Radiation Protection Organizations to determine any radiation hazard associated with the geological materials. In this paper, four distinct radial basis function artificial neural network (RBF-ANN) models were developed to predict radiation hazard indices, namely, external gamma dose rates, annual effective dose, radium equivalent activity, and external hazard index. To make RBF-ANN models, 348 different geological materials' gamma spectrometry data were acquired from the literature. Radiation hazards indices predicted from each RBF-ANN model were compared to the radiation hazards calculated using gamma spectrum analysis. The predicted hazard indices values of each RBF-ANN model were found to precisely align with the calculated values. To validate the accuracy and the adaptability of each RBF-ANN model, statistical tests (determination coefficient (R2), relative absolute error (RAE), root mean square error (RMSE), Nash-Sutcliffe Efficiency (NSE)), and significance tests (F-test and Student's t-test) were performed to analyze the relationship between calculated and predicted hazard indices. Low RAE and RMSE values as well as high R2, NSE, and p-values greater than 0.95, 0.71, and 0.05, respectively, were found for RBF-ANN models. The statistical tests' results show that all RBF-ANN models created exhibit precise performance, indicating their applicability and efficiency in forecasting the radiation hazard indices of geological materials. All the RBF-ANN models can be used to predict radiation hazard indices of geological materials quite efficiently, according to the performance level attained.

Activity concentration, transfer factor and radiological health risk assessment of natural radionuclides in soil and maize in oil producing areas in Akwa Ibom state, Nigeria

The activity concentration (AC) of 238U, 232Th, 40K of soil and maize in oil producing areas has been studied. Also studied are the transfer factor (TF) from soil to maize and the radiological health risk associated with consumption of maize. The equipment used was the Sodium Iodide-Thallium (NaI(TI)) detector. The mean activity concentration (AC) (Bqkg-1) of 238U, 232Th, 40K in soil are 12.77±0.25, 41.36±0.70 and 458.61±8.04 while that of maize are 14.36±0.27, 19.23±0.46 and 425.25±7.87 respectively. Transfer factor (TF) from soil to maize of 238U, 232Th and 40K are 1.14, 0.50 and 0.94 correspondingly. Other useful results obtained in this research include the Radium Equivalent (Raeq), Absorbed Dose Rate (ADR), Annual Effective Dose (AED) and Excess Lifetime Cancer Risk (ELCR) as 74.59 Bq/kg, 37.14 nGy/h, 0.05 mSv/y and 0.16 respectively. The average values of soil activity concentration from the oil producing areas are within world permissible limits given by UNSCEAR (2000) as 420 Bqkg-1 for 40K, 33 Bqkg-1 for 238U and 45 Bqkg-1 for 232Th. However, 238U and 232Th from maize activity concentration are far higher than world permissible limits of 0.02 Bqkg-1 and 0.003 Bqkg-1 respectively. The mean value of the radiological hazard indices was below the WMPV given as 370 Bq/kg for Raeq, 59 nGy/h for ADR, 1 mSv/y for AED and 0.29×10-3 for ELCR. This clearly shows that radiation doses exposed to Akwa Ibomites through the consumption of maize cultivated in this area poses very little to no effect to their health as only about 16 out of every 100,000 persons may likely have cancer fatality in their time.

Intake dose rate due to various granite samples of Bangalore city, India

The majority of total radiation dose received by the world population comes from background natural radiation. The distinguishing features of this radiation include relatively persistent exposure of a population at a specific place. The amount of background radiation that is generally present in the environment is greatly influenced by the inhalation of radon (Rn), thoron (Tn), and their offspring. In light of this, measurement of dose rate exposure due to granite flooring has been attempted in Bangalore. Fifteen different granite samples, used as flooring for construction in buildings, were examined for a period of three years. Solid state nuclear track detector-based dosimeters, can technique, and radiation survey meters have been used. All the experimental observations were made according to the standard protocols provided by the Bhabha Atomic Research Centre, Mumbai, India. The arithmetic mean dose rate varied between 1.39 ± 0.06 and 2.09 ± 0.10 mSv y1. The values of dose rates were found to be higher in granite and lower in coarse-grained dolerite. All 15 types of granite samples have undergone a minimum of 30 measurements. The greater activity concentration of radionuclides found in granite samples leads to higher dose rates.

Comprehensive Study of Natural Radioactivity in Building Materials: A Case Study in Ica, Peru

This study evaluates radon exhalation rates and assesses the potential radiological risks of external exposure to primordial radionuclides in building materials employed in the Ica region of Peru, particularly those with high uranium content. The radon exhalation rates are currently measured using a combination of a closed chamber and an active monitor. We proposed a novel method that effectively ensured a hermetic seal for the closed chamber and guaranteed that the efficient maintenance of secular equilibrium. The obtained results ranged from below the detection limit (BDL) to a maximum of 52.3 mBq · kg−1h−1. Gamma spectrometry was employed to measure the concentrations of radionuclides by utilizing a 3′ × 3′ NaI detector. The analysis of cement samples revealed a strong positive correlation between the activity concentration of radium and the radon exhalation rate. The activity concentrations for radionuclides varied, with values ranging from BDL to 60.6 mBq · kg−1h−1 for 226Ra, BDL to 22.3 mBq · kg−1h−1 for 232Th, and BDL to 1074 mBq · kg−1h−1 for 40K. These findings contribute valuable insight to decision-making processes in the Peruvian construction industry, particularly regarding material safety and radiological risk management.

Radiometric survey of sediments and health risk assessments from the southern coastal area of Delta State, Nigeria

Over the years, the release of potential radiological components around the oil exploration environment has increased with potential health implications.Yet; the mechanism and health associated assessment have remained fuzzy to most experimental scientists. The current study determines the activity concentration of radionuclides in sediments and the corresponding health risk assessments from the hydrocarbon exploration environment of the southern coastal area of Delta State, Nigeria. A Sodium-iodide NaI(Tl) detector, with a well-calibrated multichannel analyzer (MCA) to ensure efficiency and energy was utilized. A total of seventy-five sediment samples (Five sediment samples each per community) were collected from the southern coastal area of Delta State, Nigeria. The mean activity concentrations of 40K, 238U, and 232Th of the sediment samples were 3361.48 ± 194.26 Bqkg−1, 40.11 ± 16.17 Bqkg−1, and 45.73 ± 19.27 Bqkg−1 respectively. The obtained mean values exceeded the world standard limit of 400 Bqkg−1, 35 Bqkg−1, and 30 Bqkg−1 respectively. Also, the computed mean radiological health hazard risk of radium equivalent activity (Raeq), representative level index (Iyr), external hazard index (Hex), internal hazard index (Hin), absorbed gamma dose rate (D), annual effective dose equivalent outdoor and indoor (AEDE) and lifetime cancer risk (ELCR) values are 363.94 ± 32.37 Bkgl−1, 2.9657 Bkgl−1, 0.9839, 1.0919, 175.82 nGyh−1, 2.1556 mSvyr−1, 0.8625 mSvyr−1, and 7.5447 mSvyr−1 respectively. The values were found to be slightly higher than the world standard limit. Therefore, the residents that are using the sediments of the southern coastal area for the construction of buildings as well as dwelling in houses built with such sediments are exposed to these radiological materials. This may pose a radiological health risk concern. The obtained results will serve as radiation and radiological baseline data for sediments of the southern coastal area of Delta State, Nigeria.

Decommissioning of a Medical Cyclotron Vault: the Case Study of the National Cancer Institute of Milano.

In the widespread use of medical cyclotrons for isotope production, radiological and economic consequences related to the decommissioning of particle accelerators are often neglected. However, decommissioning regulation and its related procedures always demand efforts and costs that can unexpectedly impact on budgets. The magnitude of this impact depends strongly on the residual radioactivity of the accelerator and of the vault, and more specifically on the kind and activity concentration of residual radionuclides. This work reports and discusses a case study that analyzes in detail the characterization activities needed for optimized management of the decommissioning of a medical cyclotron vault. In particular, this paper presents the activities carried out for assessing the activity concentrations and for guiding the disposal of the cyclotron vault of the Italian National Cancer Institute of Milano (INT). An unshielded 17 MeV cyclotron vault was characterized by high resolution gamma-ray spectrometry both in-situ and in-laboratory on extracted samples. Monte Carlo simulations were also carried out to assess the overall distribution of activation in the vault. After a few months from the final shutdown of the accelerator, activity concentrations in the concrete walls due to neutron activation exceeded the clearance levels in many regions, especially close to the cyclotron target. Due to the relatively long half-lives of some radionuclides, a time interval of about 20 y after the end of bombardment is necessary for achieving clearance in some critical positions. Far from the target or in positions shielded by the cyclotron, activation levels were below the clearance level. The comparison between Monte Carlo simulations and experimental results shows a good agreement. The in-situ measurements, simpler and economically advantageous, cannot completely replace the destructive measurements, but they may limit the number of required samples and consequently the decommissioning costs. The methodology described and the results obtained demonstrated that it is possible to obtain accurate estimations of activity concentrations with cheap and quick in-situ measurements if the concentration profile in-depth inside the wall is well known. This profile can be obtained either experimentally or numerically through suitably validated Monte Carlo simulations.

Assessment of Activity Concentrations and Soil-to-Plant Transfer Factors of Natural Radioactivity in Rice Plant Components grown in Kano State, Nigeria

Transfer Factor (TF) depicts the percentage or fraction of natural radioactivity in the soil that is absorbed by different parts of a plant which are eventually transferred, directly or indirectly, to man during ingestion. Activity concentrations of primordial radionuclides were determined in farm soil and rice plant components (root, stem, leaf and seed) in six Local Government Areas (Bagwai, Bunkure, Dambatta, Garko, Kura and Wudil) renowned for production of rice in Kano State, Nigeria, using gamma-ray spectrometry method with sodium iodide scintillation detector. The mean activity concentrations of 40K, 238U and 232Th were: 509.51, 27.75, and 12.26 Bq.kg-1 correspondently in soil; 227.40, 14.24, and 5.19 Bq.kg-1 correspondingly in seed; 935.53, 32.73, and 7.29 Bq.kg-1 accordingly in leaf; 803.65, 16.72, and 6.76 Bq.kg-1 respectively in stem; and, 408.91, 30.03, and 10.31 Bq.kg-1 correspondingly in root. The mean concentrations of 40K reported in soil were greater than the world average of 400 Bq.kg-1, while those of 238U and 232Th were less than the world mean values of 35 Bq.kg-1 and 30 Bq.kg-1 respectively. The estimated mean of TFs of 40K, 238U and 232Th were: 0.52, 0.61, and 0.43 respectively in the seed; 1.95, 1.45, and 0.69 respectively in leaf; 1.72, 0.75, and 0.64 correspondingly in the stem; and, 0.85, 1.27, and 0.76 accordingly in the root. Except for a few plant samples where BDL were recorded for 238U and 232Th, all values of TFs were greater than the recommended values of 4.9 x 10-3 and 2.1 x10-4 given for 238U and 232Th...

Internal dose rate due to intake of uranium and thorium by fish from a dam reservoir associated with a uranium mine in Brazil.

Uranium mining can cause environmental impacts on non-human biota around mine sites. Because of this, the reduction in non-human biota exposure becomes an important issue. Environmental radioprotection results from the evolution of human radioprotection; it is based on dose rate to non-human biota and uses, as a biological target, and has harmful effects on populations. In the present study, a flooded impoundment created following dam construction in a uranium mine plant undergoing decommissioning was investigated. Internal dose rates due to activity concentration of natural uranium (Unat) and 232Th in omnivorous, phytophagous, and carnivorous fish species were estimated. Radionuclide activity concentrations were obtained by spectrophotometry with arsenazo III in the visible range. The dose rate contribution of 232Th was lower than that of Unat. There were no differences between the internal dose rates to studied fish species due to 232Th, but there were differences for Unat. A dose rate of 2.30·10-2µGy∙d-1 was found due to the two studied radionuclides. Although this value falls below the benchmark for harmful effects, it is important to acknowledge that the assessment did not account for other critical radionuclides from uranium mining, which also contribute to the internal dose. Moreover, the study did not assess external doses. As a result, the possibility cannot be excluded that dose rates at the study area overcome the established benchmarks for harmful effects.

Evaluation of radiological health risk caused by the use of fly ash in cement and concrete production and its storage

ABSTRACT As a result of firing pulverized coal in thermal power plants, enormous amounts of fly ash (FA) are produced as industrial waste. The release into the atmosphere and storage of this industrial waste remains one of the major environmental problems that threaten human health by contributing to air, water, and soil pollution. The recovery and reuse of FA in the construction industry is the only economic solution to the existing problem. In this study, the potential radiological risk caused by the usage of FA in concrete and cement production as a main component and its storage in landfill sites was evaluated for people and works by estimating radiological parameters (activity concentration and alpha index, annual effective doses, and the corresponding excess lifetime cancer risks) based on activity concentrations of terrestrial radionuclides in FA. Also, the radiological risk to the workers working in the FA landfill site was evaluated using the Residual Radioactivity Onsite 7.2 code. The average activity concentrations of terrestrial radionuclides in FA samples from the Tunçbilek lignite coal-fired thermal power plant at Kütahya province of Turkey were measured as 417, 156 and 454 Bq kg−1 for 226Ra, 232Th and 40K, respectively. When using up to 35% by mass of FA in cement and concrete, the average values of the radiological parameters revealed that they were within the recommended safety limits. However, code estimations showed that a regular worker in FA storage would be exposed to a total effective dose rate greater than 3 mSv y−1.

A Study on Determination of Natural Radionuclide Concentrations in Tap Water Samples Collected from the Districts of Sinop Province, Türkiye

Since Turkey's second nuclear power plant is planned to be built in Sinop province, it is very important to determine the background levels of radioactivity in this region. In the present study, activity concentrations of 226Ra, 232Th and 40K natural radionuclides in nine tap water samples collected from the districts of Sinop province located in the north of Turkey were determined using a high purity germanium detector (HPGe). The coordinates of sampling areas were also recorded by GPS device (Magellan Explorist 510). The mean activity concentrations of 226Ra, 232Th and 40K radionuclides in the studied waters were calculated to be 1.74 ± 0.49 Bq/L, 1.39 ± 0.35 Bq/L and 5.32 ± 1.41 Bq/L. In addition, annual effective dose equivalents from the intake of these radionuclides in the tap water samples were calculated for infants, children and adults and the found results were compared with the values recommended by international organizations. As a result, there is no risk in terms of natural radioactivity in the consumption of studied waters by humans.

A Comprehensive Radiological Survey of Groundwater Resources in Artisanal Mining Communities in the Eastern Region of Ghana: Water Quality vs. Mining Activities

In recent times, groundwater has emerged as an alternative drinking water source for populations in Ghana’s gold mining communities due to high pollution levels in surface water resources caused by artisanal miners. This study presents the findings on different radioactivity levels in groundwater, their sources, the characteristics of aquifers in the study area, and the impact of radionuclides on human health as a factor of water quality. The mean activity concentrations of radionuclides in groundwater samples were 0.1 ± 0.04 Bq/L for Ra-226, 0.36 ± 0.05 Bq/L for Ra-228, and 1.41 ± 0.10 Bq/L for K-40. The activity concentration of 228Ra exceeded the World Health Organization (WHO) guideline level of 0.1 Bq/L. The elevated levels of Ra-228 in groundwater were found to be of natural origin, emanating from the aquifer rocks in the study area. Groundwater resources near mining zones showed higher radioactivity levels. The corresponding committed effective dose from consuming such groundwater was estimated to be higher than the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended value of 0.3 mSv/y for children and infants, indicating potential health risks.